The goal of this Phase III study is to assess the safety, tolerability, and efficacy of OKZ in subjects with moderately to severely active RA who have responded inadequately to MTX. The primary endpoint of the trial is at Week 12. Olokizumab is expected to reduce the disease activity and improve physical function. The study is expected to provide safety information in a large group of subjects over at least a 24 week period. Adalimumab 40 mg q2w SC has been included as the active comparator for assay sensitivity and non inferiority evaluations.